At the present time, one of the most rapidly expanding technologies in data processing is that of electronic document distribution to produce an automated office environment. This technology utilizes communication networks in an office-information-interchange system or electronic mail. Such a network is a complex interconnection of processing terminals or work stations of varying capabilities performing an assortment of data processing and text processing operations with respect to document production and distribution. A major problem that such networks present is the variety of interfaces and data forms which must be accommodated to functionally interconnect the various participating work stations and processors into an operational information-interchange system. In a conventional document distribution, not only must the various processing terminals be functionally interconnected but the system must provide the basic capability to enter and edit information, distribute information and print or display information. Irrespective of the network configuration, the system must be easy to use if it is to be effective. Also, the complexities of the various interface and data forms must be transparent to the users. In other words, the system must handle and distribute the documents with a minimum of operator intervention. To expect the sender of information to know very much about processor and data form requirements is unrealistic. The sender should be able to request that information be distributed. He should not have to be concerned about the expedients used in such a distribution.
To this end, the art has been developing uniform data streams which are discernible by the various processor-work stations participating in the document distribution network. Architectures have been defined which specify data stream content as well as the rules involved in the communication in the network. These data stream architectures specify the form of the information by describing the syntax and meaning of allowable elements in the data stream. Reference is made to the article entitled "Electronic Information Interchange in an Office Environment" by M. R. DeSousa, IBM Systems Journal, Vol. 20, No. 1, 1981 distributed Feb. 16, 1981, at page 4. This article describes a typical document distribution or interchange architecture which permits information to be carried from a sender to a recipient in such a network without requiring that both be interactively communicating during the distribution process. Further, it permits a sender to send information such as a document to multiple recipients with a single distribution request. Finally, the distribution architecture provides for services such a security base storage during distribution and confirmation of delivery.
In data distribution networks, a uniform data stream may be considered to comprise two major components: the above described document interchange architecture which relates to communication and processing of the document and the document content architecture which is representative of the content and format of a particular document.
The document interchange architecture involved in the distribution and processing of documents in distribution networks is described in even greater detail in the article entitled "The Document Interchange Architecture: Member of a Family of Architectures in the SNA Environment", by T. Schick et al, IBM Systems Journal, Vol. 21, No. 2, 1982 distributed May 21, 1982, at page 220. Because of the wide variety of data processing equipment available in the current office environment together with the need to make document distribution network readily compatible with equipment which may be made available in the future, document distribution networks must have the capability of integrating into the system communicating processors of varying levels of data processing capabilities. Existing document distribution systems such as those described in the above mentioned articles provide for a uniform data stream whereby data processing stations or work stations with varying data processing capability may communicate with each other by following the protocol of the document interchange architecture. However, distribution systems problems arise when a document from a processor of higher capabilities is communicated to a processor or work station of lower or limited processing capabilities. This problem would be further complicated when it is necessary to further transmit the same document to a subsequent processor having greater or expanded data processing capabilities. This type of interchange may arise in many situations. For example, assume that a data stream containing relatively specific and sophisticated parameters with respect to document display is transmitted to a processor in the network which has very limited display capabilities and cannot process these specific parameters. After this receiving terminal has completed its processing requirements with respect to the document represented by the data stream, e.g., printing the document, it may become necessary for the data stream representative of the document to then be forwarded from this less sophisticated receiving processor to a more sophisticated processor which has the specific and complex display parameter processing capability. There is a need for the processor to have the ability of transmitting the original data stream intact to the final work station.
A similar need arises when a data stream representative of a document is to be transmitted to a less sophisticated processor station which performs some processing function and then onto the more sophisticated data processor. Here again there is a need to pass the data stream intact through the intermediate data processing station to the more sophisticated file station.